Drill for rock, coal, and other material.



S. S. WYER.-

.. iLL POR ROCK, 00M., AND 'OTHER MATERIAL.

APPLICATION FILED JAN.,14, 1905.

, Patented July 30,1912.'

6 SHEETS-SHEET1- S. S. WYER. DRILL PoR ROCK, GOAL, AND OTHER MATERIAL.

. APPLICATION FILED .TAN.14, 1905.

Patented @1151301913 6 SHEETS-SHEET 2.

' S. S. WYER. A DRILL POR ROCK, GOAL, AND OTHER MATERIAL.

APPLICATION FILED J'AN.14, 1905.

I s.- s. WYER. DRILL FOR ROCK, GOAL, AND OTHER MATERIAL.

APPLICATION FILED .TAN.14, 1905.

Patented July 30, 1912.

e SHEETS-SHEET 4.'

S. S. WYER.

DRILL FOR. ROCK, GOAL, AND OTHER MATERIAL'.

APPLICATION FILED JAN.14, 1905,

Patented July 30, 1912.

6 SHEETS-SHEET 5.

S. S. WYER. v DRILL PQR ROCK, GOAL, AND OTHER MATERIAL. APPLICATION FILED JAN. 14, 1905. 1 ,034,052. Patented July 30,1912.

- 6 SHEETS-SHEET 6.

I :To all whom. t mag/concern:

Be it known that I, SA-MUEL'S. WYER, a.

I UNITED sTATEs 'PATENT OFFICE.

SAMUEL s. WYER, or COLUMBUS, OHIO, AssIGNoR, BY MnsNE ASSIGNMENTS, To THEl Jnrrnnr MANUFACTURING COMPANY, A CORPORATION OF OHIO.

DRILL Fon ROCK, COAL,

AND OTHER MATERIAL.

I ine/.11052.V

Y .Specification of Letters Patent. Application filed January 14, 1905. VSei'al 110.241,07.

Patented lQ Iuly 30, 1912.

citizen of the United States, residing at Columbus, in the county of Franklin-and Statel of Ohio, have invented certain new and useful Improvements in Drills for Rock, Coal,

` and other Material, of. which the following is a specification, lreference beinghad there in tothe accompanying drawing.

Thisinvent-ion relates to. improvements in rill mechanisms-used for drilling rock, coal y l and similar materials.

' The improvements pertain to drills in which the work is accomplished by one or more reciprocating bodies. Many of themI pertain more particularly to drills of the i* 4class `now commonlyfk'nown as drills ofthe hammer type, that is,tho`se in which the bits orAcutting tools are not reciprocated by the prime motor `directly but have blows imparted `to them through intermediate re-` :ciprocating mechanism. Figure 1 is a vertical longitudinal. section. Fig. 2 is a transverse section on line A B of Fig. 1. Fig. 3'is a crosssection of drill.

bit Online C D of Fig. 1. Figa 4 is a cross section on line E F of Fig. 1,- and shows the valve mechanism. Fig. v5 is "a horizontal lon- 'gitudinal section on line G H of Fig. 1. Fig. 6 is a cross'section on line I J of'Fig.'v 5, and shows the drill bit holder. Fig. 7 is a cross section on line K L of Fig. 5, and shows the' ratchet and pawls. Fig. 8 is a side elevation of the yoke end of the driving cylinder and shows the method of locking the adjusting screw. Fig. 9 is a cross sect-ion of. the flexible coupling on line `M N of Fig. 1. Fig. 10 is a plan View `of the screened opening for a'dwith the motor removed andthe reciprocating mechanism' shown at the outer end of its, path of travel.- Fig. 12 is a cross sectiononline 0 P of Fig. 11, and shows the oil hole for lubricating the hammer.V Fig. 13. is a' horizontal section on line .Q R of'Fig. 11. Fig. 14 is a cross section online S T of Fig. 13, and shows the drill bit holder in position to allow the removal or insertion of the drill- Fig. 19 is a plan view. Fig. 20 is a side elevation of the guidel frame. Fig. 21is a side'v mitt-ing air to the machine. Fig. 11 is a v er` tical longitudinal section of the machineelevation of .the shell and also shows the method of closing the drill shank hole at the ing the drill, together with the spider and buifers by which the gear is secured to the shaft.

The prilne mover is an electric motor. It is shown in Figs. 1,16, 17, 19'and 22, and it is of the inrclosed type. 1 lis the frame, 2-2 'represent armature bearings with bushings 3, oil cups 4 and covers 5. To facilitate the .handling Ao1 the motoiiwhcn it is detached from the machine, the frame is fitted with a handle 6. The power of the motor is transini-tted to the drill by means of the flexible coupling shown in Figs. 1 and 9, where 7 is the armature shaft fitted with aA spider S, the latter being equipped with two rubber buffers 9., When the armature 'shaft revolves, the buffers'bear against the shoulders 10 of the flanged rim 11 which is an integral`part of the pinion shaft 12 and thereby rotates shaft 12. The pinion 13 is rigidly securedto shaft 12 by'nieaiis of a key 13l` and the washer 14. 15 is a renewable bushing which fits into the neck of the cover 16.V 17 -is an oil cup with a cover 18.- The pinion 1.3 meshes with the gear 19; 20 is the Crank shaft which works in the renewable bushing 21, the latter being held in the sleeve 22. y 23 is a spider which is rigidly secured to crank. `-;shaft 20- and contains the rubber buffers 24. The gear 19 as shown in Fig. 2 has lugs which fit into the samel annular groove that holds buffers 24 in Fig. 1. As gear 19 revolves thesel lugs compress the buffers 24 and 'therebvy cause spider'23 to rotate. The object of the bujfers .24 is to form an elastic connection between the gears and the crank `shaft and thus reduce the danger of break- (age of the gear teeth .to a minimum. 25 is' a collar that holds,` gear 19, spider 28 and buifers24 in position.' 26 is an 'oil chamber that is supplied with oil through-'the valve 27 which is normally heldV closed by the spring 28. 29 is an oil plug that is screwed into-cover 16. The cover 16 and sleeve 22 form an oilptight chamber within which the gears 13 and 19 operate. `This chamber is vtilledrv'ith oil in order to provide proper lubrication for the gears and by opening the 29 provides an opening through valve 27, the oil is allowed to iow downward into the oil chamber 26. A removable plug which oil may be poured into the casing. y

The sleeve 22 has a tight lit in the neck 231 and is keptI in alinementby the plug 32. The lower end of crank shaft has a disk 33 and crank pin 34, the latter working in the.l sliding block or cross headv 35 which rei'ciprocates inthe yokeBG of the driving cylinder 87. The lower side ot yoke'36 is covered with a steel plate 3S. to keep cross heat 35 from slidingoit of the crank pin 34. The j joil trom chamber 26 flowsl .down through theopenings shown and is carried out to crank pin 34, cross head 35 Aand yoke mi 3Q byl centrifugal force,- i.

' Screw-41mm a hciagonalv head as sho-wn in' "llhe lost niotionbetiveen cross-head andfyoke 3G is adjusted by means of the wedges 39 -mid 4.0,the latter having a nut ne"end in which'tlie screw 41 works.

rig, s

` 42 is a small plunger. ofl two 'diameters which is pushed out bythe spring'43, the smaller diameter of plunger 42 coming out y and just touching the flat side of the hexagonal yhead of screw 41 and thereby preventlngfthe latter from turning.

-44wis ajplug that is screwed into the shell 45. Itis evident that by reinovingfplug 44 and bringing the' driving cylinder to such a lposition that screwf41 is opposite the opening made the removal of plugv 44. that a socket wrench` may be inserted over the hex- `agonal "head, pushing back plunger v42 and tlien `adjusting thescrew 41. After the requisite adjustment has beeninade to screw 41, it isV only necessary to so turn the hexag` onal head that onevotits sides will be in the position shownv in Figs. '5 and 8 and thus allow plunger to come out and lock the head in that position. j

The inside -o the shell 45 Vis fitted with a renewable bronze bushing 4G in which the drivingcylinder 37 recijirocates.

and ring 47.

. "47 is an annular ring that is screw/ed into cylinder and has working lit on the hai-inner 49, the latteralso has a working lit von the inside ot cylinderfz37.

/ 4S is an air cushion between hammer 49 50 isa stop orthe hammer 49 and is secured to the shell by, means of the bolts 51 shown in: Fig., 2Q, Theiliainmer 49v has, a @working fitin the bushing52 and over the drillshank 53.. c A A lThe: rotation of th'ehammer and drill bit is aecon'iplished by means'l of the ratchet shown `in Fig. 7. k54 is a Afeather which -transiifiits the rotary motion ot-haininer 49 to drill sliank'. is the pawl carrier that holds the ypawls 5G and springs 57. 58 is the ratchet nut which has ratchet teeth on the exterior andthreads 59 on its interior= the washer 7,9 and pin` 80.

the periphery of the hammer having threads cut on it to correspond with threads 59. 60 is a pin for holding spring 57 in position. The pawl carrier 55 is held between shell 45 and the drill hea-d (S1 by the bolts (S2.

The drill bit-'holder is shown in Figs. 1, 5, 6, 11, 13 and '14.. 63 is the -holder plate which has a hole made by the intersection ot' the two sectors of circles, the smaller sector corresponding to the smaller diameter of the drill shank 58 and the other be- Ying large enough to allow the drill shank to lpass through when plate 63 is moved so as to -inake the larger sector concentric with the drill shank ,ask shown in Figs. 13 and 14. 64 is 'a bolt with a T-head having a sliding tit in the slot of plate 63. The springf acts against the nut 65 and thus holds plateA 63 and bolt G4 in the position shown vfin Fig.

' 71 -is a union sleeve screwed into drill 'head G1 and is litted with a female pipe union 72. The object. of this connection is to'admit water to,?and1lead .it down to the cutting edge of the drillvbit'.. rllie water enters through the opening in sleeve 71 then `passing through theslot 7 3 goes to groove 70 and out through the opening 7 4 to the tube 75 and thence down to the cutting edges of the drill bit. The slot 73 is required to take care of the longitudinal movement vof the drill 'shank 53, the-amount of travel being about.' three eighths'ot an inch'. Therefore. by means of Agroove 70 and slot 73, sleeve 71 can always-supply.opening 74 with water regardless otl' what the rotative or longitir dinal position of the latter may be.

The .methodi of attaching the motor to Ithe machine is shown in Figs. 1, 16, 17, 18. 21 and 22, three rubber bullers being used to form the connection.4 7 6 is a buffer, the

upper' end being secured to the motor frame by means of the split washer 77 and bolts 7 8, washer v7-7 being split .on a diameter passing through the two bolt holes:- The lower end of each Abutter 76 tits into a circular pocket on the machine and is held in position by The lower end of butler 76 is of such a thickness that when pin 80 is in position it compresses the larger flange or buffer 76. 80 isa pin which has a flat surface on one side adjacent. to the head which allows the pin to take the position shown in. Fig. 17. The pin being nut 91.-

'by the. spring 111.

vThe object of valve 110 is to keep' pushed up by the pressure from the flange or butler 76 which Was compressed -When `the pin was driven into position. Thus the continuous V-npvvard pressure from butler 76 prevents pin 8O from Working out of-place. To remove pin 80 it is only necessary yto turn it through 180 degrees and it may then be easily Withdrawn. By virtue of their construction and position these buffers absorb nearly all of the vibration from the striking of the drill bit andy relieve the motor vfrom the continuous shocks, thereby' greatly increasing its life and e'thciency.

The valve mechanism is shown in Figs'. 1, 4 and 10, Where 81 is a Wire gauze screen over the inlet air opening 82. 83 is an outlet air chamber connected to an inner air chamber 84 by meansorl apuppet valve which is actuated by a spring 86. Value-l 85 has a long hub 87 that slides on'v the stem 88 which is ari-integral part of the piston 89 andextension stem 90, the lat-ter having a 92 is a valve body that is screwed into the shell of the machineand contains thepiston 89 and forms the'seatfor valve 85. valve body'92 and -contains the spring 94. Byturning nut 93`the compression of spring f 94 and the resulting pressure against nut 491 may be varied at Will.

95 is ha delivery chamber connected to chamber 84 by 'means of thepuppet valve 96 which has a seat 97. 98 is a spring for actuating valve 96, the latter sliding on the spindle 99 Which isan integral part of seat 97, spindle 99 and seat 97 being connected by means of ribs'. 100 is aplug that is screwed into the shell 45, its object being to make the puppet valve accessible. 101 is a port connecting chamber with the air chamber 106. 102 is a port connecting chamber 84 With the drivin-g cylinde'r chamber 107 shown in'Figs. 11 and 13. 104 is an air chamber connecting the piston 89 with chamber 106 by means of ports 103. The operation of this valve mechanism is shown diagrammatically on sheet 5 of the out of chamber 106 by means of the connec tion shown at the upper side of plug 108. 109 isa combination valve, seat and union sleeve. 110 is a. valve held against its seat 112.is a female pipe union. dirt out of chamber 106 when the machine is not in useA l The machine is attached to the guide frame as shown in Figs. 1, 15, 16, 17, 20 and 21.

frame 117.. .The tooth 1-18 is also apart of frame 117 andts intothejaw119 v'vhich 93 is an adjusting nut that Works inv conveying the Water from 118 is a stud that is fastened to plug` 108 and has a nut 114 with a circular shoul-4 'is an integral part of theshell 4'5. the feed Screw nut, 4

The' energy from the electric' motor is'. transmitted to the` hammer by means of compressed air in place .of the springs that are usually used on rock drills for that pure4 pose. The air is compressed and lthe'presof the hammer is very small in comparison to original .volume of `a1r,'the` d crease 1n pressure due to the expansion is lvery small. l

YIn other Words, the air'follows lthe hammer for full stroke with almost a uniform pres'- SuI'e.

` Figs. 23, 24 and 25 are diagrams illustrat Y about twenty gallonscapacity, :which is connected tothe air chamber 106 by a hose or pipe 122.

123 is-a hose or pipe connecting tank 121' With the drill shank 53 and it is used for tank 121 to the holel in shank 53.

lIn the construction of the machine, pipe*v 122 is connected to chamber'lO'G by means of union 112, and pipe 123 is connected to opening by means of union 72, the flow of Water to opening 74 being controlled rby a needle valve 127. K

Fig. 23 shows :the first step inthe operation. Here the driving cylinder 87,- WhichV also serves as an air pump for maintaining;

the air pressure in chamber-106 is just be-l ginning its backward stroke and is drawing in air through port 102 and valve 85. 'The -'1o`5 4hammer 49 is also drawn'back through the' medium of the air cushion 48 at this stage, L

chamber 106 and the upper part oftank 121 are filled With air at. atmospheric prestion. Here the `driving cylinder and air pump 37 are near the end lof the forward stroke, having compressed the air drawn in by the previousback'strokeand forced it into the ports 101 and 103 by means of `valve 90, port 103 maintaining the same air pres-r.

that the .piston 89 can compress the springl 94 and move to the position shown in Fig. 25 Where the valve 85 has been unseated by l Y L1()v Fig.`24 shows the second step in the lopera# f e piston 89. The third step 'now takes place,

pass in 'andout of port 102 at each stroke of cylinder 37 instead of beingforc'ed into port vv'F101 andI chamber 106. Thisstep'is repeated until the' pressure in chamber' 106, port- `101 -andport/106 -is lowered by leakage vor by the airconsumption `'in tank 121 required to torce the water out through pipe 123. Just as lsoon vas the vpressure back of piston S9v is lowered a itew pounds the spring Qt'willvv f thendrawpiston 89 back and allow valve S5 to seat itself; and the'steps illustrated by pressureisagain raised' and the-steps shownl "Figsjf23 Land 24 will be repeated until the iFig. 25"Wiu'take place" `'The pfoint4 at which piston '8.9v will vunseat valve 85 yand thus fix the pressure to lbe can "riedfnin portslOl and 103,l and chamber 106 i'sdeterminedby the pressure put onspring, `94C by the nut 93;v thelatter being so arianged' as lt'o'fhe easily adjustable.` The intensity*`o;tfthe `blow struck by 'hammer t9 being depen'dentfupon the pressure carried in chamber 10G, it can thusbe easily varied f' by n'iean'sof 'the `nut 93. l l

has. not', followed 49 is 'only' at atmospheric pressure.' The valve motion just described'has" three distinct 'functionsi first, it acts as an' automatic 'safetyfvalve jsecond as-anautomatic pressure maintainer, and, third, asian adjustable .pressureregulator. Y

1 The aircushion t8 canbe `replaced-by a lrubber',lo'utterlit deemed necessary.

. vThein ac'hine as anentirety can be `readily "Separated into its three component units as' is lshown in Figs. 17, 20, 21,and'22.- To dis-v vconnect thefinotorgfit, is only'necessaiy to `re- `finove the-'three pin 'i 2carriedfvb'y the 'handle `G. To 'removeV the vmain' 'part-of the-machine from the guide frame -itjfisonly necessary to4 release'hthe nut 114. f1'255`is; a* rubber plug that -is inserted in the head' of the drill to keep out foreign ,'niattergfwhichmay ybe securedby. a chain or 'f desirable.' When the machine is so vdeachfunit is water and grit proof.' {Th'ei drivingY `vcylinder 37. has the' longitudinal groove lOrleriten'ding, as shown, tor only a portion ofits length. This groove insures' that the'pressure .upon the rear of the liammer {LQ-andthe'buler 47 will be equal until they forward end 'ot the hammer head` fi hasatlyan'ced beyond the -orward end of Wtlieigrooye', cutting ott escapeof air trom @the compression' chamber 4:8 insuring;v that i i l thecompre'ssionof the air remaining therefin will fprevent .the sudden impact of the wardby the airactingu on. its rearfaee,

andthej'ftront :socli'eted lp' linger which opcrates unoii the tool by Contact with the rear end of the drill shank. The rear end of this hammer can. then be considered' as an be considered .as

air driven piston and also as a tool actuatving piston. The front'plunger end of the hammer `can be considered as the tool operating means by whichl the energy applied to the piston-'is communicated tothe cutting- OOl. i

The shell 45, when considered together with the bushing,` 46, constitutes a motive fluid.v cylinder. The `forward end of the driviing cylinder 37 and the ring L14T constitute. a piston reciprocating within the .cylindrical shell 45. Functionally conis a. piston, and the rearwardlyprojecting; cylindrical shell by which itis connected to the yoke and power mechanism may be considered as a kind of connecting rod. ring t7 and front end of the ldrivingcylin- `der 37, in harmony with this way of designating the aboverparts of the drill, can be called the first or primary and mechanically driven piston or power reciprocated part,

has just been described as the air driven or tool actuating pist-on, can be called the secondary or' second piston.

lllhat l claim is:

l. The combination with a shell of a driving cylinder reciprocating therein, a drill, a drill operating means reciprocable within transmitting devices between said driving` cylinder and said motor, and pneumatic conneetions whereby the reciprocation of said driving cylinder in said shell supplies compressed air.to said drill operating, means, substantially as set forth.

2. The combination with a-shcll of a driving cylinder reciprocating therein, a drill`r a drill operating,` meanszreciprocable within said driving cylinder, a motor, power transmittiiig devices between saidv driving cylinder and said motor, and pneumatic connec- :tions whereby .the reciprocation of said driving cylinder in said shell supplies compressed air to said drill-operating means, substantially as set forth.

3. The 'combination with a drillof a shell, Aa dri-ving cylinder for said drill and reciprocating within said shell, drill actuatingr the-said shell and driving cylinder operat- -ing` as 'an air compressor and being,` provided with ducts for conveying the compressed air vto the interior of said driving cylinder at the rear of said head, valves for controlling the compressed air, a motor, and power transmitting means between said motor and said drivingcylinder, said power transmit- .ting mechanism comprising,- a crank moving ing cylinder.

d. The combination with a drill, of a shell, a. driving" cylinder reciprocating within said The said driving cylinder, a `rotary motor, power sidered, the front end of drive cylinder 37V e and therear end of the Vhammer Lt9 which .Y

ioo

means comprising a head litt/ed within said driving cylinder and reciprocable therein,

ina plane parallel to the axis of said driv-l shell, drill actuating means reciprocable within said driving cylinder, an air chamber .within said shell and into which said driving cylinder opens at its rear end, said driving cylinder having its other end closed and adapted to-coperate with said shell to compress air therebetween, there .being ducts in said shell and driving cylinder. for conducting the compressed air `tosaid chamber, valves for controlling said ducts, and power transmitting -devices -connected with said ,driving cylinder,` substantially as set forth. 5. The combination of a bit, an airdriven piston for actuating it, amechanically driven'reciprocating piston adaptedv to retract the air driven piston on its return Vstrokea cylindrical shell within which said" pistons have a sliding iit and lpneumatic 'connections whereby the mechanically driven piston compresses airon its forward stroke and whereby the air ,thus compressed is applied to move the air-driven piston forward,

the two pistons'being longitudinally 'independent. l p

6. The combination of a` drill bit, an air driven piston for actuating it, a mechanically driven reciprocating piston mechanically independent of the said air driven piston 4and adapted t'o retract it/ on yits return stroke, a'cylindrical shell within which said pistons have a sliding fit,'connections whereby the mechanically driven piston compresses air onits forward stroke, and

valve-controlled ducts for' leading the compressed air to the rearof the bit actuating 7 The combination with a drill, of a drill f rame or casing, 'amotor and detachable legs 7 6 for joining the'motor to the drillcasing, vsubstantially as set forth. v i

8. The combination with a drilling dev ice,'.l

of a driving mechanism, a sliding block connection between the said drilling device andv the said driving mechanism, and means substantially as described for adjusting the block.'` l 1"1 9. The. combination in a drilling mechanism with the reciprocating parts, a crank driving device therefor, of a sliding block or head 35, a guide therefor, wedge-like parts for adjusting the guide, and means for ad.

end valve controlling the flow of air'from the compressing mechanismv to the point. of application to the drill, said valves opening into the same chamber so that when the intake valve is openl the other of said valves is closed, and means for'adjusting said valves.

12. The combinationxwith a. guidev frame, of a' drill body, said body and frame being *detachably connected; at theforward, end of said frame and a clamping device securing die rear end of said frame -to-said body. i

" 13. The combination of a relatively stationary cylinder, a piston reciprocable therein, power means for reciprocating thesame, K

a second piston reciprocable within the said cylinder between the first mentioned piston 1 and-'the rear head 'of the cylinder and noi'- mally separated from said piston and rear head longitudinally by air chambers, means for maintaining'relatively high-air pressure 'in the said air chambers, and tool-operating means connected with the .second piston for being shaped to providerestricted communication between the air chambers in front .and to the rear of the second piston.

14. The chmbinat-ion of a Irelativelystationary cylinder,apiston reciprocable therein, power means for reciprocating the piston. a second piston longitudinally movable applying power to the cutting tool, the parts with respect to the first piston, disposed be tween the said first piston and the rear head of the cylinder so as to provide air chambers between it, and the said rear head and said lfirstpiston, respectively, and being provided with connections for applying power to the cutting tool, ineans'for maintaining relatively/,high air pressure in the said air chambers, the parts being shaped to provide an air-tight ,chamberl between'the two pistons when relatively close to eachother longitudinally and vto provide `restricted'com-KA 'munication between 'the' f two "air chambers'V upon the two sides of the second piston when the two pistons occupyother relative positions longitudinally.

15. The combina-tion of a cylinder, two` reciprdcable co-axially arranged pistons therein, and mechanically free to move longitudinally with respect to each other, one of the said pistons being power driven, ducts" and valves adapted in connection with the power-driven piston to provide air pressure to operate the second piston, andl means connected with the second pistonadapted to. apply power to the cutting too'l, the poweriioy driven piston4 being between the cutting tool and the second piston.

16. The combination of a cylinder, a"mo-l tor, a piston reciprocable Within the cylinder, across-head rigidly connectedto the piston, power transmitting gearing'connecting the motorwith the cross-head, and a second tool-operating piston longitudinally movable with -respect to the first piston and `torrand the eross-head..

positioned. at all ltimes between the irstpis-I 1.7. The Ycombinatie,n ofl a'fmotor, a; relatively stationary cylinder having a 'single' straight longitudinal axis, a pistonrecipro# cating therein, power-transmitting` gearing Aconnecting the motorY and the pistony and adapted to reciprocatethe latter, a second piston j-,longitudinally lmovable with respect to' thel first Y pistonre'ciprocable within'the said cylinder and located atthe rear of the first-piston, and lvalve mechanism and connections whereby the firstpistonconipresses airl upon its forward stroke, the second pist0n being driven forward by the air thus .put under pressure to apply power to the cutting tool, andretracted by the action of the simultaneously retracted rst piston.

18. The combination of a motor, a relativelystationary cylinder, a piston mechani cally reciprocated lwithin the-'said cylinder by means of the motor, a second piston longitudinally movable with respect to-the first v.piston and reciprocable within the'same cylinder between .the first piston and the rear cylinder head, means for applying air pressure to the second piston to move it on its outward stroke, -theiirst piston being adapted to alternately permit such forward moveby means of the motor', `a second piston longitudinally movable with respect to the iirst `Copies of this patent may be obtained for ment of the second piston and to retract the said motor.

v 19. vThe combination of a motor, a relasecond` piston as it is reciprocated by t-he` tively stationary cylinder,apiston mechani-A cally reciprocated within the said cylinder vpiston and reciprocable within the same cylinder between the rst piston and the rear cylinder head, means for applying air pressure. to the second piston to move it on its out-ward stroke, the first piston being adapted toalternately permit such forward movement of` the second piston and to retract thesecond piston as it is 'reciprocated by the said motor, the pistons and cylinder being yadapted to maintainan airtight space betweenthe two ,pist-ons' during such retractions.

20.The combination ofa motor, a relatively stationary cylinder, aV piston mechanicallyv reciprocated within the cylinder by vmeans of-the motor, air ducts and valves whereby.v the piston acts to compress air upon its forward stroke, a second piston arrangedI between the first piston and the rearhead of the cylinder and `reciprocable therein, means for maintaining an air cushion between they two pistons and means or conducting -the air compressed by the iirst piston upon its forward stroke to the rear of the second piston, whereby the second pistonA is constantly under air pressure tending to move it forward and is retracted periodically bythe greater air pressure of the air cushion between the two pistons when the first drawn. y y l 4 21. The combination 'of a tool actuating piston is being mechanically with- `piston, a cylinder .within which it is reciprocable, means for 'maintaining air pressure. upon the rear-face of the piston, and a power reciprocated part operatively connected at all times during both reciprocations to an enfive cents each, by addressing the Commissioner of letcnts, Washington, D. C. 

